Mercury-to-mercury double contact switch



Oct. 23, 1951 E. A. MILLER MERCURY-TO-MERCURY DOUBLE CONTACT SWITCH Filed Oct. 15. 1947 EDWI NALJGLI 5T MILLE VTT ATTy Patented Oct. 23, 1951 MERCURY-TO-MERCURY DOUBLE CONTACT swrrcn Edwin August Miller, Fairfield, Conn.

Application October 15, 1947, Serial No, 780,054

1 Claim. 1

This invention relates to mercury to mercury contact switches and especially to a double break contact of the tilting type having a noiseless snap-action.

The applicant is aware that the previous art discloses mercury to mercury contact switches, but the switch about to be described is an improvement thereon.

The objects of the invention are to provide high current-carrying capacity in a double break mercury switch; to provide in such a mercury switch double break contact with a double amount of contact air-gap as compared with that of a single break switch; to provide such a mercury switch in which sustained arcing is wholly eliminated; to provide for such a switch an off-position in which there are distinct mercury deposit at both ends of a mercury path, each of the mercury deposits at the double contact end of said path being in constant current-carrying connection with a terminal; and to provide such a switch in which a deposit of mercury, at the upper end of a tilted mercury path, is moved with a snap action to unite with and bridge the mercury deposits at the double contact end of said path, the contour of the mercury container being symmetrical and therefore reversible.

Referring to the accompanying drawing, the Figure 1 illustrates, within a casing of insulation, a mercury switch holder, the casing and holder being illustrated in outline, and the holder tilted in an ofi-position wherein the transparent glas container of mercury thereby held makes visible the mercury path in which pockets at opposite ends contain deposits of mercury, the deposits within branch pockets at one end of the path each being constantly in current-carrying connection with a terminal of which only one is shown; Figure 2 illustrates the holder tilted in an on-position wherein the mercury deposit from the single pocket at one end of the path has united with both branch pockets at the opposite end, thereby making contact with both terminals of which only one is shown; Figure 3 illustrates a transparent mercury container exposing therethrough the mercury path in which each branch pocket has a side opening through the glass container over each of which opening there is provided a portion of a current-carrying metal cap having connected therewith a metal band extending around the container, each portion of cap being sealed over an opening; Figure 4 illustrates a one-half portion of the transparent glass container of which the meeting surfaces of each half-part being adapted to be sealed together; Figure 5 illustrates an end view of glass container with current-carrying cap portions; Figure 6 illustrates a fragmentary detail; the Figure 7 illustrates the use of two mercury containers of which one is in reverse position within a holder from that of the other; and Figure 8 illustrate a slight modification of the mercury path.

With more particular reference to the accompanying drawing, the numeral I designates the casing of insulation material shown in outline. The forward end of the casing l is provided in Figures 1 and 2 with a wall attaching means 2 having a central arcuate front-wall portion 3 within which a slot 4 is provided. At either end of the slot 4 there is provided a rubber bumper 5 to silence the contact therewith of an actuator t sliding within the slot 4. At the opposite end of the casing l, and fixed thereto, are relatively spaced arcuate companion cradles of current-carrying metal one of which cradles l is shown in Figures 1 and 2, an end of each cradle 1 being continued and inserted within and through a passage 8 of the casing l to provide a terminal 9, as illustrated by the Figures 1, 2 and 6.

Within the casing I is the holder I0 of insulation material, shown in outline, and of which the actuator 6 is a part, the holder I0 having therein the cavity II. The holder Ill carries Within the cavity II, for a slight longitudinal movement therein, a transparent glass mercury container I2 having at one end a two-part current-carrying metal cap l3l4 sealed thereto in spaced relation, each cap part being connected to an end of a current-carrying metal band 45 extending around the rest of the container :2, and each cap-part I3l4 being pivotally seated within one of the companion cradles l.

The transparent mercury container [2 is preferably made in two parts It and ISA the meeting faces I! of the parts 16 and 16A being adapted to be sealed, one to the other, and together having a symmetrical contour for a purpose to be explained in connection with the Figure 7 showing reversed containers. In the process of making the mercury container l2 there is premolded in the said faces H of said parts [6 and IBA the mercury path I8, as illustrated as to one part by the Figure 5. The mercury path l8, as shown by the Figure 3, communicates the single mercury pocket It with the branch companion pockets 2E and 2| having between them the barrier 22 separating at that place the vpath l 8. Each of the companion pockets 202I is provided with a side opening 23 or 24 extending through the glass container l2, a current carrying metal cap-portion l3 or M being sealed to and over an opening 23 or 24 as permanent closure means therefor. Before sealing both of said openings 23 and 24, the proper quantity of mercury M is inserted through one of said openings 2324 and into the mercury path I8. v

The mercury path 18, as seen in the side view of the Figure 8, is shown to have a bed of varying depth over which the mercury deposit nor mally within the pocket 59 must pass upon the initial tilting movement of the glass container l2 to merge with retained mercury deposits within the pockets 2B and 2|. The points from which the bed of the mercury path l8 rises and falls are shown more particularly by the Figure 3. The mercury path 18 confined within the premolded faces HA and 11B of the parts ISA and I633 provides not only the bed of the mercury path it but also the remaining portions of confinement within the container 12 including the side walls of which [9A of the pocket H) are a part. From the pocket [9 the mercury :path 68 ascends along the line MB to a high ridge 18A from which the mercury path i8 descends along the line I8D to the lower ridge IBC over which the mercury deposit from the pocket I9 is .precipitated to suddenly merge that mercury deposit from the pocket I9 with the permanently retained mercury deposits of the pocket 2% and 2|, the merged deposits altogether overflowing the barrier 22 upon both sides 26A and ZlB thereof. Upon a tilted return movement of the container l2 a portion of the merged mercury deposits is precipitated over the ridge 58C and thereby suddenly is separated therefrom leaving within each of the pockets 2t and 2! only the normally retained mercury deposit each insufiicient in itself to flood the barrier-22.

The cavity II is of a length to provide at 25 slight tolerance for longitudinal'movement of the glass container 12 therein. A bow spring 26, engaging the glass container I2 and the casing l, maintains the container I2 with its cap-portions I3|4 in engagement with the cradles 1, while a shoulder 21 of the holder I is adapted to ride along the interior surface 28 of the arcuate wall 3 of the casing l upon the operation of the actuator 6.

Normally the actuator 6 lies in the position with respect to the slot 4, as illustrated by the Figure l, in which the mercury path I8 is tipped slightly upward. In that position there is maintained a substantial deposit of mercury M Within the single pocket l9 while there i constantly maintained Within each of the companion pockets 2fl2l a sufiicient quantity of mercury M to maintain current-carrying engagement of each of said mercury deposits with a terminal '9.

It is to be noted that the contour of the mercury container I2 is exactly symmetrical thereby permitting the mercury container l2 to be inserted within a holder I!) either end first. In the Figure '7 the advantage of such symmetry is illustrated where two mercury containers [-2 are held together within one holder 16 but ea'ch'in reversed position to the other whereby the branch mercury pockets -2! of one container I 2 is at opposite ends of the cavity ll of the holder ID to that of the other container l2, thereby providing means for a three-way make and break contact. 7

The Figure 8 illustrates a slight modification 4 of the mercury container IZA. In this form, instead of the openings 23-24 at one side of each of the companion branch pockets 20-21 the glass structure of the container I2A is provided with companion pockets 30-3! each having a wire 32 or 33 molded therein so as to have one wire end extending into and submerged in a mercury deposit of a pocket 36 or 3| and the other wire end connected with current-carrying cap parts 34- 35. Otherwise the modified form of mercury container I2A is identical with the preferred form I2.

In manually operating the actuator 6 from the position illustrated by the Figure 1, the holder I0 is upwardly swung half way along the slot 4 while the mercury deposit M in the single pocket l9 remains therein due to the high ridge ifiA. Upon further tilting of the holder ID the retarded mercury deposit M of the single pocket I?! plunges suddenly over the ridge I8A in mass form to merge with both mercury deposits within the companion pockets 2fl2l and over-flowing the barrier 22 with the entire mercury deposit MM within the mercury path l8 and thereby making a mercury to mercury double contact closing the circuit of the switch through the cap portions l3-'-I4, cradles l and both terminals '9.

With an initial reversed movement of the actuator 6 downwardly, the pivotal movement of the container [2 is not sufficient to cause the mass deposit MM to break up by reason of the holding ridge I retarding a gravitating movement thereof. Upon a further downward operation of the actuator 5, the mass deposit MM suddenly breaks up, leaving portions of mercury in each of the individual pockets 2fl2l and gravitating down the mercury path 18 and into the single pocket 59. The sudden breaking up of the mass deposit MM 'causes a mercury from mercury double break in the switch circuit.

The parts Id of the container l2, one-of which parts I6 is illustrated by the Figure 4, are provided with inclined meeting surfaces 1-! the lines "A and NE of which is illustrated by'the Figure 8. Although the meeting surfaces I! along the lines HA *and HB are not illustrated'by the Figures 1 and-2, it is to be understood that the container [2, in eachof the Figures 1, 2 and 8, is of identical structure with respect to the parts I6.

I claim:

A mercuryto mercury double electrical switch contact comprising an elongated insulation actuator mounted upon 'a base for tipping movement thereon, a single pocket 'within one "end of said actuator, multiple pockets also within said actuator at the opposite end thereof and positioned along-side one-another, each of -said'multiple pockets having an opening, a conductive metal closure provided by'each of said openings, each of said closures including a terminal, a single passage 'connectingsaid single pocket'with said multiple pockets a-barrier'with which the floor of said passage is provided between said multiple pockets there dividing the course of said passage terminating in both multiple pockets, a ridge of elevation also provided by said fioor intermediate said course, normally se'parate deposits of mercury placed in each of said multiple pockets within which their respective metal closures are submerged, a substantial mercury deposit placed in said single pocket to an overflowing extent within said passage, and means for tipping said actuator in either direction; whereby, upon a longitudinal tipping of said actuator,

mercury from said single pocket flows speedily UNITED STATES PATENTS along said passage to said ridge from which it Number Name Date suddenly plunges down both sides of said barrier L688 217 whalen Oct. 16 1928 and overflowing said multiple pockets and around said barrier thereby making simultaneously a 5 FOREIGN PATENTS full double contact with said closures.

Number Country Date EDWIN AUGUST MILLER- 4,297 Great Britain Feb. 19, 1913 REFERENCES CITED The following references are of record in the 0 file of this patent: 

